Yes, @scruss is probably right. I think I wouldn't save the image but capture to numpy array
then convert to PIL Image
. I don't know if that will then have exif editing available (or if it's tied up with jpeg). I check it out later if I get chance.
PS I think reading the exif info is a lazy operation i.e. the full file isn't read into memory until you try to use an Image function that requires it. Writing is probably a different kettle of fish.
PPS After a quick look I would say writing exif info onto a PIL Image created from numpy array isn't trivial. I think Pillow has plans to introduce more exif functionality in the future but at the moment probably better to use another module - assuming there turn out to be problems using the method you've already got working!